Republican Senator John McCain has said American leadership was stronger under President Barack Obama, according to a report.

McCain made the remarks in an interview with The Guardian published on Sunday while responding to a question.

Asked if America's stance on the global stage was better during the Obama administration, McCain responded, "As far as American leadership is concerned, yes.”

McCain, the chairman on the Senate Armed Services Committee, has often harshly criticized the policies of Republican President Donald Trump.

Nearly a month after Trump was sworn in as president on January 20, McCain said “in many respects this administration is in disarray and they've got a lot of work to do.”

In March, McCain denounced Trump’s claim that Obama wiretapped Trump Tower, saying either he has to retract it or provide evidence of the allegation.

But McCain, who lost to Obama in the 2008 presidential election, had also been very critical of the Obama administration's foreign policy agenda.

The Guardian described the Arizona senator as "visibly irked" when he was asked about Trump's recent Twitter assault on London Mayor Sadiq Khan, which came shortly after a deadly attack that left eight dead and dozens injured in the heart of the British capital.

"What do you think the message is? The message is that America doesn't want to lead," McCain said. "They are not sure of American leadership, whether it be in Siberia or whether it be in Antarctica."

Trump accused Khan, the first Muslim mayor of the city, of offering a "pathetic excuse" for remarks that the US president misinterpreted about policing in response to the attack that left several people dead.

Trump tweeted that Khan had to “think fast” to excuse comments that Londoners need not be alarmed after the deadly attack.

The US president’s provocative comments caused outrage among top British officials. Even British Prime Minister Theresa May, a Conservative, expressed her support for the mayor, a member of the Labour Party.